Highlight Shop Units Currently in Use
Currently there is no distinction for units which would contribute to your composition. Say you're collecting pirates, and a Miss Fortune pops up while refreshing. Sure, she's gold. but what if it's just a Gangplank? Or that 3rd Graves you need for an upgrade?
Im suggesting that these are highlighted with a star or a glow of one of a couple colors just to make them less likely to be skipped over. If they would contribute to your team based on type make them flash green, or add a green star on their picture. If they are currently in use on your team, use a gold highlight, and if they would complete an upgrade use red to be super obvious. You might even add a confirmation on refresh.
Obviously add toggles so as not to affect people who don't feel they need these prompts, however I feel that they would be useful without adding too much clutter or irritation.